Metal Concentrations and Bioaccessibility in Metro Vancouver Urban Parks Soils

Abstract

Urbanization increases metal emissions through varying anthropogenic activities (fossil fuel combustion). With urban parks being sinks for emissions, this study attempts to determine metal concentrations and bioaccessibility in Metro Vancouver urban park soils. Fifty-six soil samples were collected from 23 parks and analyzed for total metals by x-ray fluorescence (XRF). An analysis of 20 samples by inductively coupled plasma – mass spectrometry (ICP-MS), showed some variation in the presence and concentration of some metals as compared to XRF. Bioaccessibility (>50%) was identified for Cd, Cu and Pb, implying risk of absorption by humans (especially children) may be high. However, mean concentrations of these metals were below the CCME Soil Quality Guidelines (SQG) for residential/parkland use, suggesting human health risk associated with these metals was low. Regression analysis between pH, organic carbon and metal bioaccessibility shows pH and organic carbon accounts for a 6 to 71% variation in metal bioaccessibility.